Exercise 3

1. Explain DNS and DHCP.

Domain Name System (DNS) is the hierarchical naming system for the computers connected to the internet or a particular private network. It is always running in a server which stores all the computer's naming conversions within the domain. The main function of a DNS is to convert the human understand computer hostnames or internet domain names into Internet Protocol (IP) address. For a universal internet DNS server, it always stores all the registered domain names around the world. Of course, there are different levels of DNS servers act as authoritative name server which will handle sub-level naming conversion request. It will make the DNS system becomes distributed, fault-tolerant and avoid a single point of failure.

Dynamic Host Configuration Protocol (DHCP) is a networking protocol used by the network clients (equipment which require IP address) to obtain IP address and other necessary network parameters (DNS server). It is a client-server based design which the DHCP client will broadcast the network information request to the network, the DHCP server will respond and send back the IP address and network parameters. All those dynamic data will have expiration, therefore depending on the client OS design, they need to request the DHCP data refreshment from time to time. Without the DHCP service, all the clients need manually configure for the IP address and network parameters.

How does DNS differ from DHCP configuration?

As describe above, DNS only store the naming conversion within the domain and DHCP is responsible for the network information assignment. They are totally differing from each other, but in the real world, they are always working together. DHCP helps to distribute the DNS server IP address to all the clients and all the clients can use the DNS server content to go out to the Internet.

2. Why is it important for your online business application to use a static IP address rather than have it dynamically assigned?

Static IP address is almost a must because an online business customer will use internet browser to access the online application by typing in the site name (www.onlinebusiness.com). Such internet naming conversion is handling by the DNS server pointing by the customer's computer. We need to understand that the DNS servers around the world are not using real time synchronization and it takes a huge time for doing so. If the online business application is not using static IP address, the customer's DNS server may not have the correct IP address pointing to the online business server. Therefore, the customer cannot reach the online application and there is no business happens. Customer will not wait and re-visit the online business site again afterward. E-commerce is a 24 X 7 business.

3. What role can the following play in business-to-business e-commerce?

a.Virtual Private Network (VPN)

VPN is important for business-to-business e-commerce as it provides a secure tunnel for data exchange underlying the network traffic (internet). Without VPN, business-to-business e-commerce will need to go through a dedicated lease line which is too expensive and not flexible.

b. Next generation of wireless mesh networks

The wireless mesh networks will enlarge the coverage of the internet in the rural area and moreover it can provide a more stable and expandable networking environment than the wired ad hoc network. For e-commerce this is very important as high good quality coverage implies more business opportunities.

c. Social Cloud applications

Social Cloud applications will help the e-commerce business to cut down the application developing cost and time. Moreover, in business-to-business environment, using social cloud application means both sides are starting from the same ground. Therefore, the integration and communication between e-commerce will become seamless.

4. If clouding computing is the 'balck box', then grid computing is a component as the 'white box'.

Explain what you interpret about that statement.

Grid computing is a cluster of computers using a parallel processing architecture where the CPU resources are shared across the network acting as one large computer. Cloud computing is a set of dynamically scalable, virtual services over the Internet. (Eustace, 2010)

From my point of view, such statement is true if we are looking from a computer hardware standpoint. For grid computing, we can absolutely understand the infrastructure of the system, the amount of resources that can be allocated and more likely the system performance. For clouding computing environment, everything is unknown. We don't where the data is located, the system performance and reliability.